Nico Williams had given Spain the lead inside the opening ten minutes after Dutch full-back Jorrel Hato had lost possession deep inside his own half.

Liverpool's Cody Gakpo equalised just before the half-hour mark and the Netherlands then took the lead 39 seconds into the second period after a low shot by Tijjani Reijnders.

It looked as though Spain's unbeaten run in all competitions was going to end at 16 matches - with their previous loss a 1-0 friendly defeat by Colombia in March last year - before a dramatic final quarter of an hour.

Hato's night got worse when he was dismissed on 81 minutes and Spain took advantage by securing a last-gasp point in the third minute of injury-time through Merino's finish, after Brighton goalkeeper Bart Verbruggen had parried Williams' low shot into his path.

The second leg will be held in Valencia on Sunday, with the winners facing either Croatia or France in the semi-finals.

Cucurella's Chelsea team-mate Pedro Neto was also in Nations League quarter-final action but the forward had a less enjoyable night back in Parken Stadion in Copenhagen.

Neto would have curled Portugal in front against Denmark early on had it not been for a fine save by Kasper Schmeichel.

Chelsea defender Renato Veiga - on loan at Juventus - conceded a penalty midway through the first half but Christian Eriksen's spot-kick was saved.

It didn't stop Denmark, who had Chelsea goalkeeper Filip Jorgensen on the bench, from being victorious though as Manchester United striker Rasmus Højlund came off the bench to score the winner with 12 minutes of normal time remaining.

Portugal will be looking to bounce back from the 1-0 deficit in Lisbon during the second leg on Sunday.